2010 Concorde trial Question (Me Rappaport-lawyer) At what time was considered the fire risk following a burst tire? Answer (Mr Arslanian BEA director) After study of the events , we found no fire risk

Confidential note Mr Guillevic (BEA) 1979 Whatever the results of the investigation in progess, the Washington incident and previous incidents highlight the seriousness of the possible consequences of a burst tire: fire hazard from hydraulic flow or fuel elements of the gear overheated or burning, severe damage to the engine, the impossibility of lifting gear and limiting the braking ability , combination of two or more of these possible effect

It's possible M. Arslanian never saw the 1979 memo prior to the 2000 accident, it being 21 years old by then. More importantly the 1979 memo is clearly referring to an investigation in progress (presumably by the NTSB) that was later completed and published resulting in modifications that were thought to minimise or remedy the risks from a burst tyre. He's well within his rights to say what he's saying because the modifications to equipment and procedures over the intervening years were expected to have all but eliminated the risk of fire from a tyre burst.

I should have pointed out in my previous post that all Concorde tyre debris-related incidents between 1979 and early 2000 resulted in the same type of external piercing damage which was not considered to present a significant fire hazard. I reiterate - the one and only time the damage caused a burst from inside and a significant fuel leak was the F-BTSC accident.

Correction on Clinton accepted (although the phrase was used by the presiding judge over the "Judicial Watch" lawsuit against the Clinton Administration). If you'd like to point out where I'm wrong on the other matters, I'm happy to hear it. Supporting evidence preferred.

Once and once only will I be your monkey (no offence, but while I'm all for objectivity and truth I'm still suspicious of being played for a fool).

Using both the search function and a visual check of all occurrences of the word "tyre" or "tire" (for our transatlantic cousins) I can find no post referring to AF not reporting tyre failures. Outside of the fact that it would be extremely difficult to do so because such incidents are required to be reported by regulations, I have to conclude that if such a post ever existed it was retracted, or it was misread.

The closest thing I can find is AZR's post early in the thread which states his opinion:

Quote:

Originally Posted by AlphaZuluRomeo

Indeed, I think AF/French authorities in general took "too lightly" some issues with the plane (namely: tyres, and the Michelin NZG fitted for the return to flight were an excellent thing).

But that's a long way from saying they didn't report tyre burst issues, which would be a serious breach of protocol.

Confidential note Mr Guillevic (BEA) 1979 Whatever the results of the investigation in progess, the Washington incident and previous incidents highlight the seriousness of the possible consequences of a burst tire: fire hazard from hydraulic flow or fuel elements of the gear overheated or burning, severe damage to the engine, the impossibility of lifting gear and limiting the braking ability , combination of two or more of these possible effect

As Dozy pointed out, this note was written during the investigation of the Washington incident and as such correctly points out the possible consequences that should be considered in that investigation. This should be read in conjunction with section 1.16.4.2 of the BEA report which describes the results of that investigation and the modifications that were applied as a result.

You're linking those two facts into a theory that makes you (almost?) accusing people back in '79 to have said: "let it crash, it doesn't matter". Really? Can't you imagine other theories? Or do you choose not to mention them because they do not correspond to a certain (preconceived?) idea you might have?

Let's try again, shall we?

1/ The BEA wrote a confidential memo. Yes. Question is: why?

Perhaps at the time it was written, it was simply a work document, classified as confidential "by default" as is usual in most organizations: Only approved communications are made public. And before that, documents relative to an on-going inquiry are not meant to be public. Do we have the date of that memo? Clive answered the question while I was writing this. We now have an answer]

« O tempora, o mores ». This was 1979, 30+ years ago. The cold war. No Internet, no Web (ARPANET was just live, for US military only). Far less transparency then than now exists.

And there was political pressure about Concorde at the time: Let's not forget that flight restrictions in NY / USA were just lifted (IIRC) after a long and painful "battle". Bad publicity would have jeopardized the future operation of the aircraft (which had only recently entered service), giving "ammunition" to his opponents.

2/ Lessons from '79 did not prevent Gonesse. Indeed. But this undeniable fact has too often been distorted into "nothing was done" or something like that. This distortion is wrong: Fixes were implemented after Washington'79 and other tyres events, before the 2000 crash, and this was already stated numerous times in this very thread (among others). Those fixes were aimed at correcting/solving the issue with the tyres. They didn't succeed (enough). But we can only say that with hindsight.

Washington'79 and Gonesse were different events regarding the importance of the fuel leak (hence the importance and destroying capabilities of the consecutive fire). And the difference is not a little one, see my #59.

Conclusion: I have no difficulty imagining the political leaders of the time (IIRC the issue had risen to the presidency) decide to remain discreet and try to control the information made ​​public. With our current mindset, we can find it "weird" or even suspect. But when we remember the time and conditions ... it does not seem so suspect anymore, IMO. Even if we wouldn't accept such things anymore: the world has changed!

But the fact that discretion was required does not automatically means that the people advocating for that discretion were refusing to fix the issue at hand.

I cannot imagine, OTOH, that people (from BEA, DGAC, AF, French gov...) were convinced that there still was a great risk of accident after the fixes were implemented. I cannot imagine they have deliberately limited the range of the fixes, that would have meant they didn't care if a Concorde took fire and crashed later.

I cannot imagine, OTOH, that people (from BEA, DGAC, AF, French gov...) were convinced that there still was a great risk of accident after the fixes were implemented

How much "tires incidents" after Washington accident and the subsequent fixes ? Is the fixes were the solution to the risks confidentially described in 1979 ?

Quote:

Fixes were implemented after Washington'79 and other tyres events, before the 2000 crash, and this was already stated numerous times in this very thread (among others).

Nobody disputes the fact that fixes were made after 1979 The fact is, whether these were the good fixes to the potential risks Is that all risks have been taken into account to determine the solutions to bring ? Or is that some risks have been set aside by the use of comforting statistics ?

The fact is, whether these were the good fixes to the potential risks Is that all risks have been taken into account to determine the solutions to bring ? Or is that some risks have been set aside by the use of comforting statistics ?

With hindsight we know that the fixes applied were not enough to protect against fuel tank failure arising from a hydraulic shock inside the tank. But bearing in mind that this failure mechanism was completely unknown at that time (at least in the civil side of the industry) we can judge whether the fixes applied were consistent with giving adequate protection against the 1979 state of the art from section1.16.4.2 of the BEA report.

The relevant parts of that section state:

Quote:

Risk of fire. Based on the data about the leak in the accident, the study concluded that the risk of fire was limited, considering: o that the size of the penetrations and the rate of flow of the leak are sufficiently low; o that ignition cannot be caused by rubber or metal debris penetrating the tank; o that the fuel leaks from tanks 6 and 7 follow the flow under the wing and remain generally parallel to the aircraft axis without meeting areas of separation and thus dissipate via the wing trailing edge .The secondary nozzle’s temperature is too low to ignite the fuel; o that fuel from leaks in tanks 5 and 8 may accumulate in the landing gear well. Only the electrical circuits in this compartment constitute a possible source of ignition; o that ignition of the fuel on contact with hot brakes would not definitely occur, bearing in mind the average temperature reached by the brakes; o that in case of penetration of the tanks forward of the air intakes, leaks would be limited (due to the limited size of the debris taken into consideration) and could only enter the engine at a very low speed (after landing) and at a high thrust level

Most of the solutions then proposed were in fact put into effect and were the subject of Airworthiness Directives:• AD of 14/01/8, applied from 21/01/81, calling for the installation of a system for detection of main landing gear tyre under-inflation. An improved version of this system was then applied by AD on May 15 1982,• AD of 14/01/81, applied on 21/01/81, calling for improvements in protection in the normal braking hydraulic system,• AD of 5/05/82, applied on 15/05/82, defining an inspection procedure for the main landing gear tyres and wheels before each takeoff,• AD of 5/05/82, applied on 15/05/82, calling for the installation of new reinforced wheels in order to limit damage in case of contact with the ground and for new reinforced tyres capable of bearing twice the normal load (the regulations require one and a half times).

As a result of studies carried out on the risks of damage from pieces of tyre and on trials performed at the CEAT in 1980 to justify the integrity of the structure in case of direct penetration, it was concluded that it was not necessary to install protection for the underside of the wings.

1.16.4.2.2 Other EventsAll of the tank penetrations that occurred after the Washington event involved aircraft operated by British Airways. It should be noted that after the modifications carried out after this event, tank penetrations following a tyre burst were caused only by secondary debris. In most cases, this debris came from the destruction of equipment located in the landing gear area, probably dislodged by pieces of damaged tyre. The parts in question include the water deflector and the gear door latch.

Everyone will have their own view on this I'm sure - I'm staying out of it !

Not only for Concorde had the tyres' explosion possible various issues. DGAC was already in the glue of absolute SOPs theory to limit captain's autority and destroy SNPL and other French Pilots Unions. DGAC was not able to let the Captain reject T/O after V1 in case of tyre explosion. LFPG had the best firemen in France, would they had to extinguish the plane fire on the RWY 08 and not in Gonesse they could save lifes.

I'm convinced things should (must) change @ DGAC (perhaps change is already on the way, at last I hope so) but that's not the point.

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DGAC was not able to let the Captain reject T/O after V1 in case of tyre explosion.

I was under the impression that V1 meant just that: no more reject T/O. Why would DGAC (alone?) change that? I'm not sure that advocating for an exception (a derogation, once again?) is such a good idea.

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LFPG had the best firemen in France, would they had to extinguish the plane fire on the RWY 08 and not in Gonesse they could save lifes.

I can't comment on firemen quality. But the BEA calculated the speed at which Concorde would have overrun if the T/O had been rejected (two hypothesis, depending on when the T/O reject would have been initiated). The figures were impressive (74 kt or 115 kt) (the entire § is quoted in my post #138). And there is the cargo zone 1,200m after the threshold, with parkings & buildings. I understand from the report that Concorde overruning would not have created a situation with better chances of survival. The exact wording is:

Quote:

These figures show that an aborted takeoff would have led to a runway excursion at such a speed that, taking into account the fire, the result would probably have been catastrophic for the aircraft and its occupants.